There are more. Than one fungus the more common culprits are the dermatophytes. There is trichophytum rubrum and metagraphytes. These are the 2 main culprits.
Most common. T. Rubrum, t. Mentagrophytes, are the main ones. There are others less common.
None. Athtletes foot is not caused by a bacteria but by a fungus. There are different types of fungus. The most common is trycophytum but others such as microsporum can also infect the foot. Lamisil, (terbinafine) micatin and undecalynic acid are over the counter medicines available for treating foot fungus. Prescription are necessary for resistant cases.